Hey everyone

I’m having trouble getting Supabase Authentication (email + Google login) to work after deploying my Next.js app to Railway.

Everything works perfectly on localhost:3000, but in production (on my Railway domain) the login/signup process fails.
In the browser console, I get errors like:

[Supabase] Environment variables missing in production environment (Google OAuth)
URL: ❌, KEY: ❌

Here’s what I’ve already done:

• Added NEXT_PUBLIC_SUPABASE_URL and NEXT_PUBLIC_SUPABASE_ANON_KEY in Railway’s Variables section (same as my local .env.local)

• Checked that supabaseClient.ts uses process.env.NEXT_PUBLIC_SUPABASE_URL and process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY

• Verified that my Supabase “Site URL” and “Redirect URLs” are correctly set (including my Railway domain)

• Redeployed (and even rebuilt) the app multiple times

Despite all this, Supabase still can’t find the environment variables in production — it keeps saying they’re missing.

It seems like Next.js can’t access the NEXT_PUBLIC_ environment variables at build time on Railway, even though they’re clearly defined in the dashboard.

Has anyone faced this before?
How can I make sure these public environment variables are properly available to the Next.js frontend in Railway’s production environment?

Thanks in advance
Any help or pointers would be hugely appreciated!